Jon Niese will take a physical today and, barring an unforeseen ailment, begin counting his money.

The Mets lefty only has to pass that physical exam to make his new five-year contract worth $25.5 million official. The deal contains two option years that could make the contract worth $46 million.

“It’s a dream come true,” Niese said after the Mets’ 1-0 victory over the Braves yesterday. “You work hard all your career for this and to get it done for an organization like this that has great teammates and a great front office, great ownership, it’s just a blessing.”

Niese said the entire process took about a week and both sides wanted a deal in place before the season started.

Niese said he has no immediate plans for his money — the deal includes a $250,000 signing bonus. He was asked if he will send back $10,000 to Carlos Beltran, who recently gave Niese that amount for a nose job the pitcher received in the offseason.

“Yeah, right,” Niese said, laughing.

* Jason Bay heard the loudest boos among the Mets players introduced before the game. Johan Santana and R.A. Dickey received the loudest cheers.

“It’s special,” Dickey said. “I think I’ve always felt a real connection with the New York Mets fan base. I feel like I relate to them and they can relate to my story.”

* Santana’s Opening Day start was his fourth with the Mets. Over those four starts he has posted a 1.52 ERA, with four earned runs allowed over 23 2/3 innings. Santana also made three Opening Day starts for the Twins. … Ronny Cedeno entered the game in the ninth inning as a defensive replacement for Daniel Murphy at second base.

* Josh Thole was called out at second base by umpire Phil Cuzzi on a force play in the seventh inning despite the fact Tyler Pastornicky was clearly off the bag. But Collins said he didn’t consider arguing the call.

“The throw beat [Thole] and one of the things in the big leagues, you’re going to get called out even though he was off the bag,” Collins said. “I told Josh, ‘Please run next time — run faster.’ ”